CN202710662U - Ground insulation resistance detection circuit of photovoltaic grid-connected inverter - Google Patents
Ground insulation resistance detection circuit of photovoltaic grid-connected inverter Download PDFInfo
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- CN202710662U CN202710662U CN 201220403668 CN201220403668U CN202710662U CN 202710662 U CN202710662 U CN 202710662U CN 201220403668 CN201220403668 CN 201220403668 CN 201220403668 U CN201220403668 U CN 201220403668U CN 202710662 U CN202710662 U CN 202710662U
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Abstract
The utility model discloses a ground insulation resistance detection circuit of a photovoltaic grid-connected inverter. The ground insulation resistance detection circuit includes a photovoltaic battery voltage detection circuit, a microprocessor, a switch resistance circuit, and a lower bridge arm voltage sampling circuit arranged between the cathode of a photovoltaic battery and the ground. A first terminal of the switch resistance circuit is connected with the ground. A second terminal of the switch resistance circuit is connected with the cathode of the photovoltaic battery. A control terminal of the switch resistance circuit is connected with a first I/O port of the microprocessor. A first terminal of the lower bridge arm voltage sampling circuit is connected with the ground. A second terminal of the lower bridge arm voltage sampling circuit is connected with the cathode of the photovoltaic battery. An output terminal of the lower bridge arm voltage sampling circuit is connected with a second A/D input port of the microprocessor. The ground insulation resistance detection circuit can realize the on-line real-time measurement of the ground insulation resistance on the anode of the photovoltaic battery and the ground insulation resistance on the cathode of the photovoltaic battery and guarantee the safe and reliable operation of the photovoltaic grid-connected inverter.
Description
Technical field
The utility model relates to the photovoltaic combining inverter technical field, relates in particular to the insulation against ground resistance detecting circuit of photovoltaic combining inverter.
Background technology
In photovoltaic combining inverter, the output voltage of photovoltaic cell is higher, and the size of photovoltaic cell insulation resistance relative to the earth is significant for the safety, power grid security and the personal safety that guarantee photovoltaic combining inverter.In the prior art, usually adopt the detection method of bridge balance principle that the positive and negative electrode insulation against ground resistance of photovoltaic cell is measured, the defective of this method is that when the positive and negative electrode insulation against ground of photovoltaic cell descended on an equal basis, this technology can not detect the variation of insulation against ground resistance.
Summary of the invention
The utility model provides a kind of insulation against ground resistance detecting circuit of photovoltaic combining inverter, and it can realize the online in real time measurement of the anodal insulation against ground resistance of photovoltaic cell, photovoltaic cell negative pole insulation against ground resistance.
The insulation against ground resistance detecting circuit of photovoltaic combining inverter, comprise photovoltaic cell voltage detecting circuit, microprocessor, the first test side of photovoltaic cell voltage detecting circuit is connected with the positive pole of photovoltaic cell, the second test side of photovoltaic cell voltage detecting circuit is connected with the negative pole of photovoltaic cell, the output terminal of photovoltaic cell voltage detecting circuit is connected with an A/D input port of microprocessor, also comprises the lower bridge arm voltage sample circuit between switched resistor circuit, photovoltaic cell negative pole and the ground; The first end of switched resistor circuit is connected with the earth, and the second end of switched resistor circuit is connected with the negative pole of photovoltaic cell, and the control end of switched resistor circuit is connected with an I/O port of microprocessor; The first end of lower bridge arm voltage sample circuit is connected with the earth, and the second end of lower bridge arm voltage sample circuit is connected with the negative pole of photovoltaic cell, and the output terminal of lower bridge arm voltage sample circuit is connected with the 2nd A/D input port of microprocessor.
Wherein, also comprise warning circuit, warning circuit is connected with the 2nd I/O port of microprocessor.
Wherein, also comprise Boost circuit and inverter circuit, Boost circuit and inverter circuit are connected with the pwm signal port of microprocessor.
Wherein, microprocessor is the DSP microprocessor.
Wherein, switched resistor circuit comprises the subtest circuit, the subtest circuit comprises subtest resistance R 0 and the switch S 1 that controlled by microprocessor, and subtest resistance R 0 is connected with switch S 1, and the subtest circuit is connected between the negative pole and the earth of photovoltaic cell; Lower bridge arm voltage sample circuit comprises resistance R 1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitor C 1, C2, amplifier U1A; The model of U1A is LM258, R1 resistance+R2 resistance+R3 resistance+R4 resistance=R6 resistance+R7 resistance+R8 resistance+R9 resistance, R5 resistance=R10 resistance; The end of R1 is connected with the earth, the other end of R1 is connected with the end of R2, the other end of R2 is connected with the end of R3, the other end of R3 is connected with the end of R4, the end of the other end of R4 and R5, the end of C1, the 3rd pin of U1A connects, the other end of R5, the other end ground connection of C1, the end of R6 is connected with the negative pole of photovoltaic cell, the other end of R6 is connected with the end of R7, the other end of R7 is connected with the end of R8, the other end of R8 is connected with the end of R9, the end of the other end of R9 and R10, the end of C2, the 2nd pin of U1A connects, the other end of R10, the other end of C2, the 1st pin of U1A is connected with the 2nd A/D input port of microprocessor.
Wherein, switched resistor circuit also comprises Drive and Control Circuit, and Drive and Control Circuit comprises resistance R 11, R12, R13, triode Q1, diode D1; Switch S 1 is relay K 1, the 1st pin of K1 and the 2nd pin are the two ends of coil, the 3rd pin of K1 and the 4th pin are the two ends of normal open switch, the end of R12 is connected with an I/O port of microprocessor, the end of the other end of R12 and R13, the base stage of Q1 connects, the other end of R13, the grounded emitter of Q1, the 2nd pin of the collector of Q1 and K1, the positive pole of D1 connects, the 1st pin of the negative pole of D1 and K1, the end of R11 connects, the other end of R11 connects power supply VCC, the 4th pin of K1 connects the negative pole of photovoltaic cell, and the 3rd pin of K1 connects the end of R0, and the other end of R0 connects the earth.
The utility model beneficial effect: the insulation against ground resistance detecting circuit of photovoltaic combining inverter, comprise photovoltaic cell voltage detecting circuit, microprocessor, also comprise the lower bridge arm voltage sample circuit between switched resistor circuit, photovoltaic cell negative pole and the ground; The first end of switched resistor circuit is connected with the earth, and the second end of switched resistor circuit is connected with the negative pole of photovoltaic cell, and the control end of switched resistor circuit is connected with an I/O port of microprocessor; The first end of lower bridge arm voltage sample circuit is connected with the earth, and the second end of lower bridge arm voltage sample circuit is connected with the negative pole of photovoltaic cell, and the output terminal of lower bridge arm voltage sample circuit is connected with the 2nd A/D input port of microprocessor.The utility model circuit is realized simple, measuring accuracy is high, can realize the online in real time measurement of the anodal insulation against ground resistance of photovoltaic cell, photovoltaic cell negative pole insulation against ground resistance, and then judge whether the anodal insulation against ground resistance of photovoltaic cell and photovoltaic cell negative pole insulation against ground resistance satisfy the safety requirement, microprocessor is according to testing result control interlock circuit and equipment, thereby the assurance photovoltaic combining inverter is worked safely and reliably.
Description of drawings
Fig. 1 is the principle schematic of the insulation against ground resistance of the utility model photovoltaic combining inverter.
Fig. 2 is the block diagram of the insulation against ground resistance detecting circuit of the utility model photovoltaic combining inverter.
Fig. 3 is the circuit diagram of the insulation against ground resistance detecting circuit of the utility model photovoltaic combining inverter.
Embodiment
Referring to Fig. 1 to Fig. 3, below in conjunction with accompanying drawing the utility model is described in detail.
The insulation against ground resistance detecting circuit of the photovoltaic combining inverter of the present embodiment, comprise photovoltaic cell voltage detecting circuit 2, microprocessor 4, the first test side of photovoltaic cell voltage detecting circuit 2 is connected with the positive pole of photovoltaic cell, the second test side of photovoltaic cell voltage detecting circuit 2 is connected with the negative pole of photovoltaic cell, the output terminal of photovoltaic cell voltage detecting circuit 2 is connected with an A/D input port of microprocessor 4, also comprises the lower bridge arm voltage sample circuit 3 between switched resistor circuit 1, photovoltaic cell negative pole and the ground; The first end of switched resistor circuit 1 is connected with the earth, and the second end of switched resistor circuit 1 is connected with the negative pole of photovoltaic cell, and the control end of switched resistor circuit 1 is connected with an I/O port of microprocessor 4; The first end of lower bridge arm voltage sample circuit 3 is connected with the earth, and the second end of lower bridge arm voltage sample circuit 3 is connected with the negative pole of photovoltaic cell, and the output terminal of lower bridge arm voltage sample circuit 3 is connected with the 2nd A/D input port of microprocessor 4.
Photovoltaic cell voltage detecting circuit 2 can adopt isolation sample circuit or difference sample circuit; Lower bridge arm voltage sample circuit 3 can adopt isolation sample circuit or difference sample circuit.
In the present embodiment, the insulation against ground resistance detecting circuit also comprises warning circuit 5, and warning circuit 5 is connected with the 2nd I/O port of microprocessor 4; Also comprise Boost circuit and inverter circuit 6, Boost circuit and inverter circuit 6 are connected with the pwm signal port of microprocessor 4.Wherein, microprocessor 4 is DSP microprocessor 4.
It below is wherein a kind of concrete structure of switched resistor circuit 1 of the present utility model and lower bridge arm voltage sample circuit 3.
Switched resistor circuit 1 comprises the subtest circuit, the switch S 1 that the subtest circuit comprises subtest resistance R 0 and controlled by microprocessor 4, and subtest resistance R 0 is connected with switch S 1, and the subtest circuit is connected between the negative pole and the earth of photovoltaic cell.
Lower bridge arm voltage sample circuit 3 comprises resistance R 1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitor C 1, C2, amplifier U1A; The model of U1A is LM258, R1 resistance+R2 resistance+R3 resistance+R4 resistance=R6 resistance+R7 resistance+R8 resistance+R9 resistance, R5 resistance=R10 resistance; The end of R1 is connected with the earth, the other end of R1 is connected with the end of R2, the other end of R2 is connected with the end of R3, the other end of R3 is connected with the end of R4, the end of the other end of R4 and R5, the end of C1, the 3rd pin of U1A connects, the other end of R5, the other end ground connection of C1, the end of R6 is connected with the negative pole of photovoltaic cell, the other end of R6 is connected with the end of R7, the other end of R7 is connected with the end of R8, the other end of R8 is connected with the end of R9, the end of the other end of R9 and R10, the end of C2, the 2nd pin of U1A connects, the other end of R10, the other end of C2, the 1st pin of U1A is connected with the 2nd A/D input port of microprocessor 4.Need to prove, R1, R2, these four resistance of R3, R4 can use a resistance to replace, and R6, R7, these four resistance of R8, R9 also can replace with a resistance, and these two replace the resistance of resistance to equate.
Switched resistor circuit 1 also comprises Drive and Control Circuit, and Drive and Control Circuit comprises resistance R 11, R12, R13, triode Q1, diode D1; Switch S 1 is relay K 1, the 1st pin of K1 and the 2nd pin are the two ends of coil, the 3rd pin of K1 and the 4th pin are the two ends of normal open switch, the end of R12 is connected with an I/O port of microprocessor 4, the end of the other end of R12 and R13, the base stage of Q1 connects, the other end of R13, the grounded emitter of Q1, the 2nd pin of the collector of Q1 and K1, the positive pole of D1 connects, the 1st pin of the negative pole of D1 and K1, the end of R11 connects, the other end of R11 connects power supply VCC, the 4th pin of K1 connects the negative pole of photovoltaic cell, and the 3rd pin of K1 connects the end of R0, and the other end of R0 connects the earth.The present embodiment cooperates with K1's by R11, R12, R13, Q1, D1, and control R0 is connected with the photovoltaic cell negative pole, certainly, also can select other can realize the Drive and Control Circuit of this function.
The principle of the insulation against ground resistance detection of the utility model photovoltaic combining inverter is: make the positive pole of photovoltaic cell, negative pole insulation resistance over the ground be respectively R+ and R-, consist of upper brachium pontis between the positive pole of photovoltaic cell and the earth, consisted of time brachium pontis between the negative pole of photovoltaic cell and the earth.Closure and disconnection by microprocessor 4 gauge tap resistance circuits 1, the positive pole that can obtain two groups of photovoltaic cells over the ground with the negative pole voltage ratio equation over the ground of photovoltaic cell, wherein unknown parameter is R+ and R-, by calculating the resistance value that just can obtain R+ and R-.The principle schematic of the insulation against ground resistance of the utility model photovoltaic combining inverter as shown in Figure 1, R0 is subsidiary resistance among the figure.
Insulation against ground resistance detection algorithm of the present utility model may further comprise the steps:
A: microprocessor 4 detects the output voltage signal of photovoltaic cell by photovoltaic cell voltage detecting circuit 2, obtains the voltage V of photovoltaic cell
PV
B: microprocessor 4 sends control signal, make the switch S 1 in the switched resistor circuit 1 be in off-state, this at present the output signal of bridge arm voltage sample circuit 3 be Vad1, the output signal of microprocessor 4 by lower bridge arm voltage sample circuit 3 can obtain this moment the photovoltaic cell negative pole and ground between lower bridge arm voltage u1:
C: microprocessor 4 sends control signal, make the switch S 1 in the switched resistor circuit 1 be in closure state, this at present the output signal of bridge arm voltage sample circuit 3 be Vad2, the output signal of microprocessor 4 by lower bridge arm voltage sample circuit 3 can obtain this moment the photovoltaic cell negative pole and ground between lower bridge arm voltage u2:
Wherein
,
,
Then can be obtained by formula (3), (4):
Then:
By formula (7), (8), microprocessor 4 can calculate R+ and R-online in real time by computing;
E: whether the resistance value of judging R+ and R-satisfies the safety requirement, insulation against ground safety requirement according to photovoltaic combining inverter, the positive pole of photovoltaic cell insulation resistance and negative pole insulation resistance over the ground over the ground will satisfy standard greater than 1K Ω/V, therefore, the resistance of R+ and R-will satisfy formula (9) and (10):
(9)
F: according to result of determination, carry out next step action of photovoltaic combining inverter, if the resistance of the R+ that microprocessor 44 calculates and R-satisfies the safety requirement, then microprocessor 4 allows Boost circuit and the inverter circuit 6 startup work of photovoltaic combining inverters; If the R+ that microprocessor 4 is calculated and the resistance of R-do not satisfy the safety requirement, then microprocessor 4 can drive warning circuit 5 and send alerting signal, and passes through Boost circuit and the inverter circuit 6 startup work of pwm signal port blocking photovoltaic combining inverter.
In sum, circuit of the present utility model is realized simply, computation process is succinct, accuracy of detection is high, the online of negative pole insulation against ground resistance of having realized the anodal insulation against ground resistance of photovoltaic cell and photovoltaic cell detects in real time, guaranteed that photovoltaic combining inverter works safely and reliably.
Should be noted that at last; above embodiment is only in order to illustrate the technical solution of the utility model; but not to the restriction of the utility model protection domain; although with reference to preferred embodiment the utility model has been done to explain; those of ordinary skill in the art is to be understood that; can make amendment or be equal to replacement the technical solution of the utility model, and not break away from essence and the scope of technical solutions of the utility model.
Claims (6)
1. the insulation against ground resistance detecting circuit of photovoltaic combining inverter, comprise photovoltaic cell voltage detecting circuit, microprocessor, the first test side of photovoltaic cell voltage detecting circuit is connected with the positive pole of photovoltaic cell, the second test side of photovoltaic cell voltage detecting circuit is connected with the negative pole of photovoltaic cell, the output terminal of photovoltaic cell voltage detecting circuit is connected with an A/D input port of microprocessor, it is characterized in that: also comprise the lower bridge arm voltage sample circuit between switched resistor circuit, photovoltaic cell negative pole and the ground;
The first end of described switched resistor circuit is connected with the earth, and the second end of described switched resistor circuit is connected with the negative pole of photovoltaic cell, and the control end of described switched resistor circuit is connected with an I/O port of described microprocessor;
The first end of described lower bridge arm voltage sample circuit is connected with the earth, and the second end of described lower bridge arm voltage sample circuit is connected with the negative pole of photovoltaic cell, and the output terminal of described lower bridge arm voltage sample circuit is connected with the 2nd A/D input port of described microprocessor.
2. the insulation against ground resistance detecting circuit of photovoltaic combining inverter according to claim 1, it is characterized in that: also comprise warning circuit, warning circuit is connected with the 2nd I/O port of described microprocessor.
3. the insulation against ground resistance detecting circuit of photovoltaic combining inverter according to claim 2, it is characterized in that: also comprise Boost circuit and inverter circuit, Boost circuit and inverter circuit are connected with the pwm signal port of described microprocessor.
4. the insulation against ground resistance detecting circuit of photovoltaic combining inverter according to claim 3, it is characterized in that: described microprocessor is the DSP microprocessor.
5. the insulation against ground resistance detecting circuit of photovoltaic combining inverter according to claim 1 is characterized in that:
Described switched resistor circuit comprises the subtest circuit, the subtest circuit comprises subtest resistance R 0 and is subjected to the switch S 1 of described microprocessor control, subtest resistance R 0 is connected with switch S 1, and the subtest circuit is connected between the negative pole and the earth of photovoltaic cell;
Described lower bridge arm voltage sample circuit comprises resistance R 1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitor C 1, C2, amplifier U1A; The model of U1A is LM258, R1 resistance+R2 resistance+R3 resistance+R4 resistance=R6 resistance+R7 resistance+R8 resistance+R9 resistance, R5 resistance=R10 resistance; The end of R1 is connected with the earth, the other end of R1 is connected with the end of R2, the other end of R2 is connected with the end of R3, the other end of R3 is connected with the end of R4, the end of the other end of R4 and R5, the end of C1, the 3rd pin of U1A connects, the other end of R5, the other end ground connection of C1, the end of R6 is connected with the negative pole of photovoltaic cell, the other end of R6 is connected with the end of R7, the other end of R7 is connected with the end of R8, the other end of R8 is connected with the end of R9, the end of the other end of R9 and R10, the end of C2, the 2nd pin of U1A connects, the other end of R10, the other end of C2, the 1st pin of U1A is connected with the 2nd A/D input port of described microprocessor.
6. the insulation against ground resistance detecting circuit of photovoltaic combining inverter according to claim 5, it is characterized in that: described switched resistor circuit also comprises Drive and Control Circuit, Drive and Control Circuit comprises resistance R 11, R12, R13, triode Q1, diode D1; Described switch S 1 is relay K 1, the 1st pin of K1 and the 2nd pin are the two ends of coil, the 3rd pin of K1 and the 4th pin are the two ends of normal open switch, the end of R12 is connected with an I/O port of described microprocessor, the end of the other end of R12 and R13, the base stage of Q1 connects, the other end of R13, the grounded emitter of Q1, the 2nd pin of the collector of Q1 and K1, the positive pole of D1 connects, the 1st pin of the negative pole of D1 and K1, the end of R11 connects, the other end of R11 connects power supply VCC, the 4th pin of K1 connects the negative pole of photovoltaic cell, and the 3rd pin of K1 connects the end of R0, and the other end of R0 connects the earth.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201220403668 CN202710662U (en) | 2012-08-15 | 2012-08-15 | Ground insulation resistance detection circuit of photovoltaic grid-connected inverter |
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| CN 201220403668 CN202710662U (en) | 2012-08-15 | 2012-08-15 | Ground insulation resistance detection circuit of photovoltaic grid-connected inverter |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103645383A (en) * | 2013-12-24 | 2014-03-19 | 浙江昱能光伏科技集成有限公司 | Detection circuit for insulation resistors to ground of inverter |
| CN103944506A (en) * | 2013-12-26 | 2014-07-23 | 中国电子科技集团公司第四十一研究所 | Photovoltaic array grounding impedance detection system and method |
| CN104422825A (en) * | 2013-08-29 | 2015-03-18 | 浙江万向太阳能有限公司 | Method and method for detecting insulation resistance against ground of DC power supply |
| CN104569597A (en) * | 2014-12-18 | 2015-04-29 | 北京新能源汽车股份有限公司 | Method and device for detecting insulation resistance of power battery |
| EP3376621A1 (en) * | 2017-03-13 | 2018-09-19 | Omron Corporation | Distributed power supply |
| CN112083229A (en) * | 2020-09-04 | 2020-12-15 | 爱士惟新能源技术(江苏)有限公司 | Ground insulation impedance detection circuit and method of photovoltaic inverter |
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2012
- 2012-08-15 CN CN 201220403668 patent/CN202710662U/en not_active Expired - Lifetime
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104422825A (en) * | 2013-08-29 | 2015-03-18 | 浙江万向太阳能有限公司 | Method and method for detecting insulation resistance against ground of DC power supply |
| CN104422825B (en) * | 2013-08-29 | 2017-10-27 | 浙江万向太阳能有限公司 | A kind of direct-current power ground insulation impedance detection apparatus and method |
| CN103645383A (en) * | 2013-12-24 | 2014-03-19 | 浙江昱能光伏科技集成有限公司 | Detection circuit for insulation resistors to ground of inverter |
| CN103645383B (en) * | 2013-12-24 | 2016-05-04 | 浙江昱能科技有限公司 | The testing circuit of the insulation against ground resistance of inverter |
| CN103944506A (en) * | 2013-12-26 | 2014-07-23 | 中国电子科技集团公司第四十一研究所 | Photovoltaic array grounding impedance detection system and method |
| CN103944506B (en) * | 2013-12-26 | 2017-01-04 | 中国电子科技集团公司第四十一研究所 | The detecting system of a kind of photovoltaic array impedance ground and method |
| CN104569597A (en) * | 2014-12-18 | 2015-04-29 | 北京新能源汽车股份有限公司 | Method and device for detecting insulation resistance of power battery |
| EP3376621A1 (en) * | 2017-03-13 | 2018-09-19 | Omron Corporation | Distributed power supply |
| CN112083229A (en) * | 2020-09-04 | 2020-12-15 | 爱士惟新能源技术(江苏)有限公司 | Ground insulation impedance detection circuit and method of photovoltaic inverter |
| CN112083229B (en) * | 2020-09-04 | 2023-04-11 | 爱士惟科技股份有限公司 | Ground insulation impedance detection circuit and method of photovoltaic inverter |
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